The P.I.'s immediate career goal is to acquire skills not develop during his undergraduate and graduate work which are necessary to do "bioorganic" research. These include collection and analysis of kinetics and thermodynamics data and experimental and theoretical elements of research on biopolymers. Specific projects which require these skills are currently underway, and are described. These include: 1. Study of a new family of active oxygen scavengers, the mercaptohistidines. Preliminary results on these naturally occurring substances indicate that they scavenge O2-., H2O2, alkoxy radicals, and nitroxide radicals. Further study will provide rates and mechanisms for these processes, information useful in combatting inflammation, aging, radiation damage, and cancer. 2. DNA Dynamics. A non-perturbing and rigidly tethered nitroxide spin probe has been synthetically incorporated into a duplex DNA dodecamer. This probe has a significant potential for reporting on local dynamics of DNA as a function of conformation, medium (salt, temperature), and base sequence. Further studies, involving dynamics of DNA, drug-DNA complexes are proposed. 3. Sequence Specificity of DNA Crosslinking. Several important drugs exert their effect by covalently cross-linking DNA. The nitrogen mustards and mitomycins, are examples. It has thus far not been possible to elucidate the sequence specificity for the cross-linking reactions. A simple solution to this problem is proposed. 4. Peptide Conformation. The ability to design large molecules containing precisely defined geometric shape and functionality would enable the creation of new catalysts and receptors. One solution to this problem, used by nature, is peptide folding. synthetically accessible peptides do not adopt a stable structure. We propose using a unique cyclic peptide terminating residue designed to initiate a short alpha-helix.